Telephone



Maw 18'. 1926.

J. MASSOLLE ET AL TELEPHONE Filed larch 26. 1925 3 SheetsSheet 1 n M o kn MM M 3.

i m a May 18 1926. 1,585,333

r J. MASSOLLE El AL TELEPHONE Filed larch 26. 1925 3 Sheets-Sheet 5vwcmtou 7 9 9114444681. 3%? flttomw Wgi dam, M W

Patented May 18, 1926.

UNITED STATES 1,585,333 PATENT OFFICE.

JOSEPH EASSOLLE, OF BERLIN-GRUNEWALD, HANS VOGT, OF BERLIN-WEMEBSDOM,AND JOSEF EN GL, 0] BERLIN-GRUNEWALD, GERMANY, ASSIGNOBS TO TRI-ERGON,LIMITED, OF ZURICH, SWITZERLAND, A CORPORATION OF SWITZERLAND.

'rnnnrizonn.

Application filed March 26, 1925. Serial 1T0. 18,620.

The invention relates to improvements in telephones and particularly toloud speak ing Or other receiving telephones which are adapted toreproduce sound, such as speech andmusic, with great faithfulness andabsence of distortion.

In its preferred form the invention comprises an electrostatictelephone,the invention, however, not being limited to this form.

In our co-pending application, Serial N 0. 518,425, electrostatictelephone, filed November 28, 1921, we have disclosed a tele hone, thediaphragm of which is subdivi ed by annular clamping rings into aplurality of ring shaped portions which are adapted to vibrateindependently of each other, these diaphragm portions each having anatural rate of vibration corresponding to some frequency within theacoustic range.

By the provision of a suflicient number of diaphragm annuli each havinga different natural rate of vibration, the diaphragm will have resonancepeaks correspon ing to various fundamental tones and their overtones,and by the provision of a suitable damping factor, the reasonance peaksthus formed will be flattened so that the vibration of the diaphragmwili correspond quite closely with the various frequencies which are tobe reproduced throughout the acoustic ran e.

Tie present invention is in some aspects thereof an improvement uponthat disclosed in our said co-pending application. In accordance withthe present invention a plurality of diaphragm portions are providedeach of which possesses no decided natural rate of vibration as a whole.Each of these diaphragm portions or members resonates to a plurality of.frequencies so that one of these diaphragmmembers or portions mayrespond to various frequencies within ope range while another diaphra mmember or portion responds to various requenoies extending through adifferent range. This is accomplished by the provision of diaphragmmembers or portions of irregular shapes,

- and in the preferred form of the invention this is accomplished bysubdividing the diaphragm into a plurality of annular portions each ofwhich is of a varying width. Thus the diaphragm may be clamped inposition by eccentrically arranged clamping rings so mounted as toprovide a plurality of annular diaphragm portions each of which mayincrease in width progressively through say 180, or generally speakingthroughout the arc of some radial angle of the annulus, the diaphragmannulus decreasing progressively in width throughout the remainder ofitsangular extent. With such an arrangement the variousdiaphragm portionsmay be caused to resonate to substantially all frequencies throughout anextended range. In the preferred arrangement, the highest individualnatural rate of vibration of one dia hragm annulus or portion willberather c ose to the lowest natural rate of vibration of an adjacentdiaphragm portion, it bein thus possible to produce a device in whicthere is a fairly uniform variation of the natural rates of vibration ofthe diaphragm from a very low level to a high level within the acousticrange.

An object of the invention is the provision of improved devices of thecharacter referred to above.

Other objects of the invention comprise the provision of improveddevices whereby sound may be reproduced with a minimum of distortion andpreferably by a diaphragm, the total area of which is suflicient torender the use of an amplifyin horn unnecessary, when the device is useas a loud speaker for reproducing the sound in an auditorium or thelike.

The invention accordingly consists in the improved arrangements andcombinations of arts and features of construction all as Wil be morefully describedin the following specification, and as will beparticularly pointed out in the appended claims.

In order that the invention may be more thoroughly understood attentionis hereby drawn to the accompanying drawings forming part of theinvention and illustrating by way of example certain preferredembodiments of the invention.

Referring to .the drawings, Fig. 1 represents a face view of one form oftelephone, operated electro-magnetically, and comprised within theinvention;

Fig. 2 is a vertical section taken on line 22 of Fig. 1;

Fig. 3 is a face view of a modified form of construction embodyin anelectrostatic telephone, certain parts being broken away;

Fig. 4 is a vertical section on line 4-4 of Fig. 3, taken on an enlargedscale;

Fig. 5 is a partial front elevation of a modified form of electro-statictelephone; and

Fig. 6 is a section taken on line 66 of clamping ring between which andthe sur-.

face of seating flange 3 the edge portion of the diaphragm is clamped bysuitable means such as screws 5. The plate 2 is also provided with aforwardly extending boss 6, against which the diaphragm is clamped bysuitable means such as a circular plate 7, a screw 8 being illustratedas extendin throu h member 7 and the diaphragm an into t e boss 6.

It will be noted that the center line C of member 7 and boss 6 is spacedsomewhat away from the center 0 of the dia hr The ortion of thediaphragm whic is to vi rate is accordingly an annulus of va ing width,bounded at its inner edge by t e riphery of the clam ing member 7, andEdunded at its outer e ge by the inner edge of the clamping ring 4.

In the form. of construction shown in the drawing, electro magnets 99are indicated, diagrammatically, as being supported by plate 2, inposition to actuate the iaphragm 1n res use to varying currents assingthroug the electro-magnet circuit. ny desired number of theseelectro-magnets may be used, the same preferably being spaced at pointsintermediate the clamping member 7 and the outer clamping ring 4. Itshould be understood that, if the invention be embodied in anelectro-static telephone instead of an electro-magnetic telephone, caacity surfaces will take the place of the e ectro-' magnets, similarconstructions bein described hereipafter in connection wit the followingfigures of the drawing.

In the construction illustrated in Figs. 1 and 2 the varying width ofthe vibratory diaphragm annulus causes the same to have di erent naturalrates of vibration which vary in accordance with the varying widths ofthe diaphragm as explained. The diaphragm Wlll accordingly resonate to aplurality of different frequencies throughout a more or less extendedrange.

Referring next to the form of construction shown in Figs. 3 and 4 of thedrawings, a construction 18 shown in which the diaphragm is subdividedinto a plurality of annular portions, each of varying width, and eachhavinga range comprising a plurality of natural rates of vibration. Thisconstruction is shown as applied to an electrostatic or condenser typeof telephone, which constitutes the preferred form of construction Inthe construction illustrated, a fixed condenser plate 10 is shown withwhich co- 0 rate'smovable diaphragm 11. This diap constitutes themovable element of the e ectro-static telephone and in the preferredform of construction the diaphragm is formed of insulating materialcarrying a coating 12 of electrically conducting material. Preferablythe diaphragm is formed of an exceedingly thin disc of mica, which ispreferably coated with a suitable conducting metal. The conductivecoating may, for example, be a thin silver coat deposited on thediaphragm from a solution comprising silver nitrate and othersubstances, the invention however, not being limited in this respect. lhe sheet of mica used in the dia phragm is preferably of a thickness ofonly about 3/100 of a millimeter, while the diameter of the diaphragm ispreferably quite large, as for example about meter, the invention not,however, being limited to such dimensions. It is noted, however, thatmica is particularly well adapted for use in our preferred construction,since a uniform sheet of mica may be obtained, by a splittin process sothat it is possible to obtain a s set of athickness as slight as 1/100of a millimeter, and of a diameter, for example, meter. Such extremethinness and large diameter are possible because of the high tensilestrength of the mica. The advantages of mica for the desired purpose areexplained in our co-pending application, Serial No. 518,425, referredto. In our preferred construction the diaphragm is placed under aconsiderable tension, which may be nearly as great as the elastic limitof the mica, it noted that the elastic limit of mica is exceedingly highin relation to its tensile strength. The mica stands such high tensionexceedingly well in practice. It should be noted that the exceed ngthinness of the mica diaphragm makes for lightness and absence ofinertia, and it also should be noted that the hard smooth surface of themica better fits the same for the propagation of sound waves than woulda porous or non-uniform surface.

The diaphragm is clamped against suitable seatin surfaces, whichpreferably are. integral with the fixed plate 10. In the constructionillustrated, plate if) is provided with an annular outer rim portion 13,which is concentric with the plate and against which the edge portion ofthe diaphragm may be seated. In the construction shown the plate 10 isalso provided with a boss 14 against which the diaphragm is clamped,this seating portion 14 being eccentrically situated with respect to theplate 10 and with respect to the diaphragm. 7 It will be noted that, inthe construction shown, from the center line of boss 14, at 15, issomewhat separated from the center line 16 of plate 10.

A seating ring 17 surrounds boss 14, this ring preferably beingconcentric with a point, such as point 18, Fig. 3, which is somewhatseparated from the centers both of boss 14 and the plate 10 itself. Thenthe diaphragm is clamped against seating surfaces 14 and 17, an annularvibrating por'- tion will thus be provided between seatin portions 14and 17, which will be of a widt which varies continuously, firstincreasing uniformly throughout a portion of its circumference and thenuniformly decreasing in width throughout the remainder of itscircumference.

Another annular vibrating diaphragm portion is formed between theeccentric ring 17 and an outer seating ring, which, in the presentconstruction, takes the form of a ring 19, which may be concentric withthe plate 10 itself. This outer diaphragm portion, bounded by theeccentric ring at its inner edge and the concentric ring at its outeredge, will, therefore, be a diaphragm ortion of ring sha e, generally seaking,

ut of a varying Wltfill. The space etween ring 19 and the outer edge ofthe plate 10, in the construction illustrated, is utilized fortensioning and clamping the diaphragm.

The diaphragm is clamped in position by means of a construction whichcomprises pressure rings or the equivalent, this preferably taking theform of a spider having an outer annular rim 20 and radiating spokes orarms 21. This spider construction is provided with a. boss 22 which isadapted to align with the eccentric boss 14 on plate 10 when the rim 20of the spider is aligned with the outer edge of plate 10. y The spideris also provided with an eccentric ring 23, which is adapted to alignwith the eccentric ring 17 on plate 10.. All of the parts described ofthe spider may be formed, if desired, as an integral metal construction,which may, for example, very readily be cast.

In assembling the plate, diaphragm and clamping member therefor, the diahragm is positioned against the plate 10 with conductive coating 12 onthe side of the'diaphragm away from the late. The spider may then besecured to t e plate by means of screws 24 or other suitable securingdevices passing through the rim portionZO of the spider and through theedge portion of the diaphragm and into the rim portion of plate 10.Preferably insulating material 25 is provided about each of the screws24 to prevent the formation of any creeping paths for electricalcurrents along the screws from the spider to the fixed plate. Theconductive coating 12 on the diaphragm may extend radially only so far,if desired, as the inner edge 26 of the faced clamping portion 20 of therim of the spider member, or if desired the conductive coating may hecontinued to the outer periphery of the diaphragm, which may be at theouter edge of the plate, it being noted that the mica body or base of,the diaphragm serves as an insulation between the parts.

The diaphragm may be tensioned by suitable devices such, for example, asperipherally arranged members 27, which may be carried or engaged byscrews 28 threaded through suitable openings in rim 20 of the spidermember. These pressure devices 27 may be of wedge shape or othersuitable shape, and are caused to press against the diaphragm to tensionthe latter as desired. Plate 10 may be provided with recessed portions29 in alignment with the pressure devices 27, the diaphra in beingpressed into these recesses by mem rs 27 as the tensioning proceeds.Preferably the diaphragm is tensioned up to a point quite close to theelastic limit of the mica, as statedabove.

The fixed plate 10 is provided with capacity surfaces intermediate theclamping or seating portions of the plate, which capacity surfaces areto serve as the fixed plate member of the device with which the adjacentportions of the conductive coating carried by the diaphragm will co-act.As shown, these fixed capacity surfaces may take the form of ring shapedmembers integral with the body of late 10. These capacity surfaces arere erably rings of varying widths, positione intermediate the clam ingor seating portions of the plate, the ed capacity rings being widest atpoints at which the corresponding diaphragm annulus has the greatestwidth and vice versa.

In the construction shown, one fixed capacity annulus 30 is intermediatethe boss 14 and the seating ring 17, and an outer capacity annulus 31 ispositioned interme- 115 diate rings 17 and 19. As stated, these capacitysurfaces are preferably formed of varying widths. Thus the annularsurface 30 may be bounded on the inside by a circle 32, the center ofwhich is at a point 32', 120 while the rin 30 is bounded on the outerside by a circfia 33, the center of which is at a different point such,for example, as point 33'. Similarly the outer capacity annulus 31 is ofvarying width having its inner and 12 outer ed es bounded by circleswhich are formed a outdifferent points as centers. It will be noted thatthe construction described gives the capacity surface in each instance avarying width, which may be widest at a 130 point at which thecorresponding diaphragm portion is the widest.

The seating rings or portions 14, 17 and 19 and the fixed capacitysurface rings 30 and 31 are provided with very accurately faced uppersurfaces so that the diaphragm when at rest will be separated from thefixed capacity surfaces by a very small gap, the capacity surfaces beingset back from the seating surfaces. This gap, for example, may be amatter of a very few one hundredths of amillimeter. The accurateestablishment of this distance, in the construction illustrated isprovided by the accuracy with which the seating surfaces and fixedcapacity surfaces of plate'lfl" are finished, and variation in the widthof the gap between the diaphragm and the fixed capacity surfaces isprevented by the fact that the parts which establish the gap are allformed of metal, having the same co-eiiicient of expansion throughout.

The close adjustment of the diaphragm to the fixed capacity surfacescauses a dam ing of the vibrations of the diaphragm, w hich damping isdesired, but not to as great an extent as would be provided by theconstruction described. Accordingly, the damping effect may be somewhatreduced by the provision of suitable openings through the condenserplate 10 through which the air in the gap between the diaphragm and thefixed capacity surfaces may escape to greater or less extent during thevibration of the diaphragm. In the construction shown the openings forthe escape of the air preferably take the form of concentric circularchannels ext-ending entirely through the fixed capacity ring portions 30and 31 of the plate 10= These circular grooves 34, in the case of theinner condenser ring 30, may, for example, be formed about the point 32'as a center. Some of these circular channels will extend entirelythrough 360, entirely around the fixed capacity portion 30 of the plate,while some of these circular channels 34 will extend through less than360 of length since they will run out through the outer peripheralsurface of ring 30, with which t ey are eccentric. The circular channels34', formed through the outer capacity ring 31, are similar. The ringsof metal intermediate the circular channels 34 and 34' are, of course,held together by suitable connecting portions of the metal which maybridge across the various circular channels at points which may, forexample, be out of alignment with each other.

In the construction described, the vibrating diaphragm portionintermediate the seating portions 17 and 18 of the plate will havevarious individual rates of vibration extending through one range ofacoustic frequencies, while the outer diaphragm annulus between seatingrings 17 and 19 will have various other natural individual frequenciesextending through a different range of the acoustic frequencies. Theouter diaphragm annulus as arranged will have a, hi her range offrequencies than the inner diap ragm annulus and the arrangementpreferably is such that the lowest natural frequency of the outerannulus is nearly the same as the highest natural rate of the innerannulus. This equalit of the lowest natural rate of the outer diaphragmportion with the highest natural rate of the next adjacent innerdiaphragm portion may be arranged by making the least width of the innerdiaphragm annulus substantially equal to the greatest width of the outerdiaphragm annulus.

\Vith such an arrangement as many eccentric diaphragm rings may bearranged one with another-as is required, so that the range of naturalvibration of the diaphragm may extend substantially from the lowest upto the highest acoustic fre uencies which will have to be reproduced. 11case such an arrangement requires a telephone having too great a totaldiameter, a plurality of such telephones may be used, and this is infact the preferred arrangement.

In the construction as illustrated, the highest frequency of onediaphragm portion may, as stated, be substantially equal to the lowestnatural frequency of the adjacent diaphragm annulus. This is evidencedby substantial equality of the smallest width of the inner diaphragmannulus, indicated at with the greatest width of the outer diaphragmannulus, indicated at d the reference characters d, d, d and (1 beingused to indicate the respective widths of the dia phragm portions fromthe bottom to the top of the diaphragm along the central Vertical axis,referring to Fig. 3. With this arrangement,however, an absolutelyuniform variation of the natural rates of vibration of the entirediaphragm is not produced. Uniform variation throughout the entirediaphragm is possible when the widths of one diaphragm portion overlapthe widths of the adjacent portion to the extent of 90 of angulardisplacement, and such an arrangement may readily be accomplished withinthe present invention. This arrangement may be used when two or moretelephones are used in place of a single one because of the fact thatone telephone would be too large, as stated above. In this case theseveral telephones may have their widths of vibratory diaphragm portionsdisplaced to the extent of 90 with reference to one another.

To make the above matter of overlapping widths somewhat clearer, itshould he noted that each diaphragm annulus increases progressively inwidth from its greatest width, as at d, to its least width, at (11',where d and d are illustrated as being on the vertior the positions?!best distribution; of resonance frequencies, therefore, the least width,d,"()f, theifinr annulus should approximately equal, not the greatestwidthE d, of the. outer annulus, but the width 0 theiouter annulus atapoint intermediate d and d, in which case width d would of a course beless than width d of the enter in. proper.

annulus aligned therewith, and greater than width d.

, The'diaphr'agm rings may and preferably rcisc calculated thatapproximately equally large surfaces are operative at all f uencieswhereby all frequencies are repro uced ropcrtio'n one to another.

d. orm'o'f construction is shown h p I h In ({his case the (ii;- pm 11a,' acon uctivecoatin is 'sec u i ed'iii po s i tl on between the fixcon denser plate and a spider member. The diaphragrn is shown as clamouter peri 'hery, by devices w ich are con centric wit .the diaphragmitself, andabout 7, one inner circle which is eccentric with the d aboutits diaphragm so as to produce a single vibratory diaphragm annulus ofvarying width,

In the construction illustrate the plate 10 has a ring portion which issecured-to an outerfianged ring 36 by means, forexample,-of-screws 37extending through a peripheral flange of rim 35' and into ring 36,insulating material 38 referably being used about screws 37 and tweentheadjacent faces of rim 35 and ring 36. The clamping or pressure applyingmember compr ses an outer concentric rim portion 39, together withradial arms 40. An eccentric ring 41 is carried by the arms 40. Clampingand pressure applying members 42 extend through this ring and areadaptedto press the adjacent portion of the diaphragm againstcorrespondingly ositioned seats 43, formed in the fixed con enser member10'.

The ring 36 to which the fixed plate 10 is secured is fastened to therim 39 of the spider member by means, for example, of screws 44 whichextend peripherally around the device. The diaphragm is secured undertension at its outer ed e by means of clamping and tensionin evlces 45,45', which extend through t e rim 39 of the spider member in twoconcentric rows one within the other.

These clamping members may comprise small wedge shaped blocks 46, 46,seated in suitable openings in the rim 39 and hearing against theadjacent surfaces of the diaphragm. These pressure applying members bearwith line contact against the diuphragm and may be forced more or loss:bers 46 and 46'.

tightly agains't"* "ijh diaphragm by the small screws 45, 45'. Suitablerecesses '47, 47' are provided in the face of ring 36 and rim.

35 of thefixed late construction respective- Z-iigwhhh t e adjacentportions ofthe 'aphragm be pressed whenthe clamp-'- members aretightened. Screws 42, ex-

tending through theeccentric ring 41, are similar I mu dw Operate P s ppying members 48, which are similar to memlithe plate 10' is providedwith-a fixed capacity surface 49 which extends in the form of a ofvarying width around the de--.

intermediate the circles alon -which t he diaphragmis clamped at 48- an'46. This annular capacity surface is only'illustrated 1nart,,since itwill be understood that its wi th may vary thrcughout its an ar ex tentin the sanie'manneras was exp ained in 35 connection with Fig. 3 Air inthe gap between. the fixed capacity surface and the diaphragm may berelieved bythe provision of channels 50 which may be formed in a similarmanner to the channels '34, described in connection withFigs. 3 and 4.The capacity surface 49 is set back sligh liy from the seating surfaceson vwhich the iaphragm will be clamped, adjacent the recesses 43 and 47so as to est blish a slight up between the fixed capacit surface and t ediaphra m as was explained in connection with the construction shown inFigs. 3 and 4. The construction maybe completed by a cover. late 51which may be secured to the rim ange 36 of the plate construction bymeans ofscrews 52 so as to cover i over t e plate construction togetherwith the screws 37 and 44. p ,j

In the construction described, the diaphragm is both clampedand placedunder e desireditension by suitable adjustment of the pressure devices48, 46 and 46, no screws or other devices assing th'rou h the diaphragmitself. It will, of course, e understoo that similar clam ing andtensioning means may beused ii desired, in connection with the form 0construction shown in Figs. 3 and 4. The fixed plate memberz aii t 10'me if desired, be constructed in the form 0 a spider instead of in theform of a solid plate, in which case the member 10' will comprise therim 35 connected to the hub 53 by means of radial arms which carry thefixed capacity surface rings 49.

It will be understood that electrical connections are to be suitablymade to the fixed and movable members of the condenser telephone. Thusin the form shown in Figs.

3 and 4 one connection is of course, made to the plate 10 and the otherconnection to a suite is point such as the rim 20 of the spider, which,of course, is in contact with t is conductive coating 12 of thediaphragm.

In the'form shown in Figs. 5 and 6 suitable connection may member 10 andwith the rim39 of the spider construction.

The device, as described, in its various forms, particularly in theforms illustrating the same, as an electrostatic telephone, isparticularly well adapted for use as a loud speaker or sound reproducer,which may be employed, for example, to reproduce sound in theaters orconcert. halls or the like. When soused, sufiiciently loud reproductionmay be given without the use of any amplifying horns or the like,whereby the errors of re roduction due to such devices are obviate andthis is obviously true because of the considerable size of the diaphragmwhich is preferably employed and'by the employment of two or moresimilar devices if necessary, as described above. In this connection itwill, of course, be understood that the electrical currents operatingthe, device may be suitably amplified as by means of the usual vacuumtube amplifiers, so that the diaphragm portions may be given asufficient amplitude of vibration in case loud re roduction is desired,It will also be noted that the device, because of its large -number ofnatural rates of vibration, provides for vibration of the diaphragm inresonance with a considerable number of acoustic fre uencies which areto be reproduced w ereby resonance peaks are formed throu bout theentire range 'of frequencies whic are to be reproduced. Dis tortion inreproduction is, however, prevented by the dampin eflect provided, sothat the resonance pea s will be flattened. Accordingly, in a graph orcharacteristic curve portrayin the operation of the diaphragm at allequencies reproduced, the tops of the resonance peaks will be connectedtogether by a smooth curve which is substantiall the same as that whichwould represent t e correct vibration of the diaphragm for the variousfrequencies if the diaphragm had no natural rates of vibration at all.That is to say, we consider it im ractical to so arrange such a largediap ragm as we prefer to use, that the natural rate of vibration of thesame will be outside the acoutic range; and, accordingly, we provide foras large a number of natural rates of vibration within the acousticrange as is possible and obtain the effects described.

It should be understood that the invention is not limited to the exactdetails of the construction which have been particularly de scribed, butthatthe same is considered to be of a considerable breadth as isindicated by the scope of the appended claims.

What I claim is: I 1. In a telephone,'thc combination of a diaphragm, aplate, and means for clamping g the diaphragm to the plate, in spar-edrelabe made with the plate tion thereto, comprising rings eccentric tothe diaphragm to provide vibratory diaphragm portions having difierentnatural rates of vibration.

2. In a telephone, the combination of a di'aphragm,a plate,- and meansfor clampmg the diaphragm immovably to the plate, about the periphery ofthe diaphragm and at a pomt eccentric with respect to the diaphragm, soas to provide a complete annuar diaphragm portion of varyin width spacedfrom said plate and surroun ing said oint.

' 3. In a telephone, the combination of 9. diaphra a plate, and meansfor clamping the iaphragm to the plate, about the periphery of thediaphragm and about a cir cle eccentric with respect tothediaphragm andintermediate the center and periphery thereof, so as to provide avibratory diaphragm portion extending completely around said circle.

4. In a telephone, the combination of a diaphragm a plate, and means forso clamping t e diaphragm to the late as to provide a plurality ofcomplete ring sha ed diaphragm portions, eccentric to the dia' hragm, ofvarying widths and having diferent natural rates of vibration.

5. In a telephone, the combination of a diaphragm, a member to which thesame is secured, and means for so clamping the diaphragm immovably tosaid member as to provide a vibratory diaphra un portion in the shape ofa complete annulus of a width uniformly increasing throughout a portionof the angular extent of the annulus, and uniformly decreasingthroughout the remainder of the angular extent of the annulus.

6. In a telephone, the combination of a diaphragm, a member to which thesame is secured, and means for so clampin the diaphragm immovably tosaid mem er as to provide a vibratory diaphra m portion in the shape ofa complete annulus of varying width, whereby the diaphragm will have aplurality of different natural rates of vibration throughout its area.

7. In a telephone, the combination of a diaphragm, a member to which thesame is secured, and means for so clamping the diaphragm to said memberas to provide a pair of separately-vibratory diaphragm portions, each inthe shape of an annulus of varying width, one surrounding the other,each annulus having a plurality of different natural rates of vibration,the rates of vibration to which one annulus responds lying within onerange, and the rates of vibration to which t e s annulus responds lyingwithin a differ. t range.

In telephone, the combination of a diaphragm, a member to which the sameis SGCUi'mi, and means for so clamping the diaphragmto said memberes toprovide a plura lit'y separately-vibratory diaphragm portions, eachinthe shape of an annulus of varyingwidthfsaid annuli being radially onewitliin' the other, each annulus having a range or frequencies to whichit resonates, the lowest natural frequency of one annulus being close tothe" highest natural frequency of the adjacent annulus on one sidethereof. 9.'In"a telephone, the combination of a diaphragm,-a fixedcondenser plate having a seating surface and a capacity surface, andmeans for clamping said diaphragm agams't said seating surface so as toprovide a vibrator annular diaphragm portion of varying wi th separatedfrom said capacity surface by a slightga 10.11; a tefdphonathecombinatlon of a diaphragm hiav' v portion of annu ar shape with varyingwidth, anannular capacity surface separated from said diaphragm by aslight gap, and means for securing said parts in position, with said diahragm under tension. l1. In a te ephone,.the combination of a diaphragmof irregular shape, calculated to resonate locall' to variousfrequencies, a plate closel a jacent to said diaphragm to produce aclamping effect, said plate'having openings therethrough to somewhatrelieve the damping effect, and means for securing said parts inposition with said diaphragm under tension.

12.11111 telephone, the combination of a diaphragm of irregular shape,calculated to resonate locally to various frequencies, said diaphragmbeing of insulating material with a conductive coating, a condenserplate closely adjacent to the insulated side of said diaphragm, andmeans for securing said parts in ,position.

13. In a telephone, the combinationoi a diaphragm having a plurality ofseparated parts each having a plurality of different natural rates ofvibration, supporting means, and means for securing sald diaphragmthereto, under tension, and for separat ng the parts of said diaphragm.

14. In a telephone, the combination of a diaphragm, a member to whichthe same is secured, and means for so clamping the diaphragnrto saidmember as to provide, a pair of separately-vibratory diaphragm portions.each in the shape of an annulus of rnrving width. one surrounding theother, each annulus having a plurality of different natural rates ofvibration, the rates of vilwnlion to which one annulus responds lyingiihin one range, and the rates of vibration which the second annulusresponds lying v'lihin a diil cnt range, the outer annulus rsponding ton higher range of frequencies than the inncr,

15. In a lclrphone, the combination of diaphragm means, comprising :1plurality of securing sai diaphragm means,

vsulating materia an eifective vibratory 'tances therefrom,

annuli of one radially wi f'n the other; porting means, and meagi' s or'i'p i 's, o of difl'erent natm al. rates of vibration, the rangeoffrequenciesof one annulus being 'difi'erentfrom the range of another,

16. In a .-telephone, the combinationof comprising a plurality ofportions of irregular shape, supporting means, and means for securingsaid portions thereto about all their edges.

17. In a telephone, the combination of diaphragm means, comprising ,aplurality of portionsof irre lar shape, formed of inand havingaconducting coating thereon, a fixed condenser plate, and means forsecurin said portions in position spaced a sli ht istance from saidplate, with the con uctive coatings on the op "osite side from saidplate, said coatings eing connected together electrically.

. 18. In a-telephone, the combination of diaphragm means, comprising aplurality of portions of irregular shape, formed of insulating materialand having a conducting coating thereon, each portion being adapted toresonate in a difierent range of he quencies, capacity surfaces spacedslight distances .from the insulated sides of said portions, and meansfor securing said parts in position and for electrically connectingtogether said capacity surfaces, and said diaphragm means portions.

19. In anelectrostatic telephone, the combination 'ofmovable platemeans, compris-r mg a plurality of irregularly shaped diaphragmportions, each portion being adapt ed to resonate .to a different rangeof fr e quencies, capacity surfaces spaced slight disand means forsecuring said parts in position and for electrically connecting togethersaid capacity surfaces, and the portions of said movable plate means.

20. In an electrostatic telephone, the combination of diaphragm means,com rising a plurality of annuli of varying w dth, lone surrounding theother, fixed means providing capacity surfaces, each comprising anannulus of varying width, spaced slight distances from said diaphragmannuli, and means for securing said means in position.

21. In an electrostatic telephone, the combination of diaphragm'means,comprising a plurality of annuli of varying width, one surrounding theother, fixed means providi'n, capacity surfaces. each comprising anannulus of varying width, spaced slight distanccs from said diaphragmannuli, and means for securing said means in position, said fixed meanshaving circular openings extending therethrongh from said capacitysurfaces.

22. In an electrostatic telephone, the comannuli theretd aboiit theirpeeach annulus having faplurality binafion of a fixed condenser platehaving" means ciii ried By said spider construction for-clamping saiddiegh'ragm against said 10 seatmg surfaces with t e diaphragm spacedslightly from said cepscity surface.

JOSEF ENGL. JOSEPH MASSOLLE. HANS VOGT.

bination of a fixed condenser plate having an annular capacity surfaceand annular seatin surfaces at the outer and inner sides of sai capacitysurface, a diaphragm comslightly from said capacity surface. 5 prising amovable condenser element, and V diaphragm-securing means. comprising aspider construction having a rim portion adapted to be secured to saidfixed plate, and

J OSEF ENGL. JOSEPH MASSOLLE. HANS VOGT.

Certificate of Correction.

It. is hereby certified that in Letters Patent No. 1,585 333, grantedMay 18, 1926', u I n the apphoation of Joseph Massolle ofBerlinrunewald, Hans Vogt, of

erhn-Wflrnersdorf, and Josef Eng}, of liverlin-Grunewald, Germany, foran improrelnent m Telephones, errors appear in the printed specificationrequiring correction as follows: Page 3, line 7, strike outthe word frompage 6, line 82, claim 3, after the word about insert thelword's theperiphery of; and that. the said Letters Patent should be read withthese mrrections therein that the same may conform to the record of thecasein the Patent ()flice..

Signed and sealed this 22d day of June, A. D. 1926.

[emu] M.J. MOORE,

Acting fi'mmmaaw' Mr of Patents.

means carried by said spider construction for clamping said diaphragmagainst said 10 seating surfaces with the diaphragm spaced Certificateof Correction.

It is hereby certified that in Letters Patent No. 1,585 333, granted May18, 1926, upon the'apphcation of Joseph Massolle of Berlin runewald,Hans Vogt, of Ber '-W ihnersdorf, and Josef Eng], of verlin-Grunewald,Germany, for an improvement in Telephones, errors appear in the printedspecification requiring corrction as follows: Page 3, line 7, strikeout-the; word from page 6, line 82, claim 3, after the word about insertthe lwo'rd's tire periphery of; and that the said Letters Patent shouldbe read with these corrections therein that the same may conform to therecord of the cast? in the Patent Oflice..

Signed and sealed this 22d day of June, A. D. 1926.

[SEAL] M.'J. MOORE,

Acting Umnmdsxioner of Patents.

